1. Technical Field
The present invention relates in general to a system and method for regulating cooling of integrated circuits. In particular, the present invention relates to a system and method for regulating fan speed based on measured temperatures of integrated circuit.
2. Description of the Related Art
Integrated circuits require heat dissipation or cooling. Some integrated systems provide cooling by merely allowing the integrated circuit generated heat to dissipate in the surrounding atmosphere or by aid of heat sinks. Other cases require external devices to provide cooling assistance. Commonly, integrated circuits are mounted on printed circuit boards that are contained within a chassis having a fan mounted to providing airflow through the chassis, in order to cool the integrated circuits.
Present practice is to provide a single speed fan in a chassis. However, as integrated circuits advance in technology and clock frequency increases, cooling becomes more of a concern. Therefore, in some systems, variable speed fans have been provided. A typical way to implement the cooling with a variable speed fan is to connect a veritable speed fan to a thermostat, which measures the air temperature inside of a chassis. Based on the ambient air temperature, the fan speed can be adjusted to provide cooling.
However, the ambient air temperature is not the best measure of the heat of a specific integrated circuit sense. A computer system contains several integrated circuits. Each integrated circuit has its own heat that needs to be dissipated. Certain integrated circuits, such as central processing units or CPUs, require a greater amount of cooling than other integrated circuits in the system. Again, it is not uncommon to provide these CPU integrated circuits with heat sinks or even a fan mounted on the integrated circuit. Thermal diodes have been used in chips to measure junction temperature of provide signals for fan speed control. Some integrated circuits provide a digital output of the temperature signal for controlling fans. However, a need exists to provide a more flexible control of cooling based upon temperature data obtained on the integrated circuit devices.